Erno Rubik - Rubik's cube

Erno Rubik (the inventor)

Life and career

Erno Rubik

Ernő Rubik was born in Budapest, Hungary, July 13, 1944, during World War II. His father, Ernő Rubik, was a mechanic-engineer, glider builder, a renowned specialist, creator of more than twenty six types of gliders at the Esztergom airplane factory, and his mother, Magdolna Szántó, was a poet and artist.^[1] He graduated from the Technical University, Budapest (Műszaki Egyetem) Faculty of Architecture in 1967 and began postgraduate studies in sculpting and interior architecture he said “The combined presence of these impulses, the technical one and the arts one, have been for me, I'm sure of it, a determining factor. At first, I tended towards the visual arts : I drew a lot and I have painted a lot. I made my secondary education in a school which was dependent upon the "Beaux- Arts", as a sculptor. From that time, my taste for technical applications awakened. So the next step in my studies naturally became the University Of Technical Education Of Budapest, and, in 1967, I obtained there my architect diploma”. After that in 1971 until 1975 he worked as an architect, then became a professor at the Budapest College of Applied Arts (Iparművészeti Főiskola). “I still have a passion for architecture, as one have the more complex activities which combines the more characteristic features of science, technical science and arts. With my diploma, I didn't feel yet like a completely well-trained man and I continued my studies at the Decorative Arts High School in the interior architecture section. My second diploma gave me the title of designer; it was given to me in 1970. These studies made me sensitive to the artistic factors. Since 1970 I have stayed constantly in the High School, teaching plans and constructions, interior architecture drawings, furniture plans and projects, study of form and descriptive geometry. Teaching is the best way to learn, I'm still convinced of that; by passing on our knowledge we continue to discover and learn. Moreover, this activity force us each time to a new formulation of what we want to express, force us to new tries, constant search of new methods. The constant links with youth help us to always have a youthful outlook, make us able to surprise ourselves constantly” Erno Rubik.

“

Space always intrigued me, with its incredibly rich possibilities, space alteration by (architectural) objects, objects' transformation in space (sculpture, design), movement in space and in time, their correlation, their repercussion on mankind, the relation between man and space, the object and time. I think the CUBE arose from this interest, from this search for expression and for this always more increased acuteness of these thoughts...

He has spent all his life in Hungary got married in 1977; his wife is an interior architect.Their little daughter, born in 1978, is called Anne.

”

Rubik's Cube

In the early 1980s, he became editor of a game and puzzle journal called ...És játék (...And games), then became self-employed in 1983, founding the Rubik Stúdió, where he designed furniture and games. In 1987 he became professor with full tenure; in 1990 he became the president of the Hungarian Engineering Academy (Magyar Mérnöki Akadémia). At the Academy, he created the International Rubik Foundation to support especially talented young engineers and industrial designers.

At present he is mainly working on video game development and architectural topics and is still leading Rubik Stúdió.

He is known to be an introvert, barely accessible and hard to contact or to get hold of for autographs. He typically does not attend speedcubing events. However, he attended the 2007 World Championship in Budapest.^[2]^[3] He also gave a lecture and autograph session at the "Bridges-Pecs" conference ("Bridges between Mathematics and the Arts") in July, 2010.

Rubik is a member of the USA Science and Engineering Festival's Advisory Board.

Other newest invention

Ernő Rubik's newest invention: the Rubik's 360

Monday, February 2, 2009
Great expectations are surrounding the introduction of Rubik's 360, on February 5, in Germany. The Rubik's 360 is the newest invention of Ernő Rubik the inventor of the phenomenally successful Rubik's Cube three decades ago. The new toy will be available world-wide in August.The expectations are high; everyone expects that the new toy will become an instant success just like the cube was three decades ago. The Rubik's 360 has numerous combinations but only one solution. It consists of three closed spheres and six colorful balls enclosed in the structure. The challenge is to rescue the balls from the enclosure.

The Rubik's Cube came out in 1980 and became an instant success. 350 million pieces have been sold and has become the number one toy around the world. The toy has also acquired the status of a work of art and as such on permanent display in the Museum of Modern Arts in New York city.
The 64 years old Ernő Rubik awarded with the Kossuth Prize in 2007. He has released a brief statement regarding his newest invention: " I think the Rubik's 360 is the most ingenious and most exciting toy I have invented since the Rubik's Cube."
After inventing the Rubik's Cube he has developed numerous other toys but none have become as successful as the Cube.

The journey of inspiration In Erno’s own words

Milestones in my life

Who influenced me – family members
My father, Ernő Rubik Sr. (1910 – 1997) was an engineer, designing gliders during his whole life with great enthusiasm. Due to his devotion to work he became Number 1 in his profession in Hungary. His knowledge of his subject earned him an international reputation too. I frequently see his planes flying in the sky while me and my beloved wife, take the dogs for a long walk to the nearby forest of Budapest. Beside him I learned a lot about work in the sense of a value-creating process which has a target, and a positive result too. Both figuratively and literally he was a person capable of 'moving a hill‘. There was nothing that could prevent him from doing what he decided or bringing a project to a completion, if necessary even with his own hands. No work was unworthy or undeserving for him. Nowadays I would call my father a ‘designer‘– an expression which did not exist in Hungary back then. He was able to understand and represent the demands and the requirements of the manufacturer as well as the user.

Teachers and other outstanding personalities

There are a number of exceptional artists from various fields of art who exerted a great influence over me through their work. The ones closest to me are the following:

Leonardo da Vinci (the Renaissance man),
Michelangelo (also a polymath, painter, sculptor, architect etc.),
Benvenuto Cellini (goldsmith, painter, sculptor),
Maurits Cornelius Escher (artist, impossible constructions, explorations of infinity),

Voltaire (writer and philosopher, Candide: Or, Optimism),
Stendhal (writer, On Love)
Thomas Mann (novelist, critic, Mario and the Magician)
Jean-Paul Sartre (philosoper and novelist, Words)
Attila József (an outstanding Hungarian poet)

Jules Verne (pioneer of sci-fi, The Mysterious Island)
Isaac Asimov (another writer of sci-fi, Foundation Series)

Frank Lloyd Wright (architect, Fallingwater House)
Le Corbusier (architect, the Modulor)

Decisive experiences and events which shaped the path of my life
Schools offered me the opportunity to acquire knowledge of subjects or rather crafts that need a lot of practice, persistence and diligence with the direction of a mentor.

I studied sculpture at the Secondary School of Fine and Applied Arts, then went on to the faculty of architecture at the Hungarian University of Technology, finally to the faculty of interior architecture and furniture design at the Hungarian University of Applied Arts (today: Moholy-Nagy University of Arts and Design).

Learning subjects, that were interesting, has always been easy for me and I had never done it for the sake of putting a tick next to the ‘box of accomplished things’. Learning gave me joy and I found fulfillment in every moment I spent with it. No wonder that I started teaching immediately after graduation. In other words I continued learning in another way. Teaching architecture and giving lectures on form studies gave me the possibility for research, and kept me stimulated for a better performance and it gave me the drive for the search of new possibilities.

Rubik’s cube (the invention)

Background

Rubik's cube is a toy puzzle designed by Erno Rubik during the mid-1970s. It is a cube-shaped device made up of smaller cube pieces with six faces having differing colors. The primary method of manufacture involves injection molding of the various component pieces, then subsequent assembly, labeling, and packaging. The cube was extremely popular during the 1980s, and at its peak between 1980 and 1983, 200 million cubes were sold worldwide. Today sales continue to be over 500,000 cubes sold worldwide each year.

History

Every invention has an official birth date. For the Cube this date is 1974 when the first working prototype came into being and a patent application was initially drafted. The place was Budapest, the capital of Hungary. The inventor's name is now a household word, Rubik's Cube.

Although 1974 marks the inauguration of the Cube, the processes that led to the invention began a few years earlier. At the time, Erno Rubik was a lecturer at the Department of Interior Design at the Academy of Applied Arts and Crafts in Budapest.

He had a passionate interest in geometry, in the study of 3D forms, in construction and in exploring the hidden possibilities of combination of forms and materials, not just in theory, but also in practice.

In the course of his teaching, Erno Rubik preferred to communicate his ideas by the use of actual models, made from paper, cardboard, wood or plastic, challenging his students to experiment by manipulating clearly constructed and easily interpreted forms. It was the realizations that even the simplest elements, cleverly duplicated and manipulated, yield an abundance of multiple forms that was the first step on the long road that led finally to the Cube.

When the Cube was complete, Erno Rubik demonstrated it to his students and let some of his friends play with it. The effect was instantaneous. Once somebody laid his hands on the Cube it was difficult to get it back! The compulsive interest of friends and students in the Cube caught its creator completely by surprise and it was months before any thought was given to the possibility of producing it on an industrial scale.

During 1978, without any promotion or publicity, the Cube began very slowly to make its way through the hands of fascinated youths into homes, playgrounds and schools. The word of mouth spread and by the beginning of 1979 there were enthusiastic circles of Cube devotees in various parts of Hungary.

Undeterred by the universal rejection, spurred on by his firm belief in the exceptional quality of the toy, Tom Kremer, now armed with a convincing marketing plan, continued his search for a viable partner. After many disappointments, he succeeded in persuading Stewart Sims, Vice President of Marketing of the Ideal Toy Corporation, to come to Hungary, to see with his own eyes the Cube in play. It was now September 1979, by which time the Cube has gained a sufficient degree of popularity to be seen occasionally in the street, on trams, in the cafes, each time in the hand of someone turning and twisting and completely absorbed. After five days of convoluted negotiations between a sceptical American capitalist and an obstinate communist organization largely ignorant of the operation of a free market, with Laczi and Kremer holding desperately the two sides together, an order for one million cubes was signed amidst much handshaking and great relief all round.

The challenge of trying to master the Cube, to be able to restore all of its six sides to the original colours seemed to have a mesmeric effect on an amazing variety of individuals right across age, occupation, wealth and social standing. Grandmothers, bank managers, baseball players, pilots, librarians, park attendants could be seen working away at their Cubes at any hour of the day. In restaurants the Cube would feature on tables side by side with salt and pepper pots, handled with greater frequency than either. But it was the young, schoolboys and students, who were in the vanguard of what was fast becoming a massive movement that swept through the world. They were the ones who proved most adept at solving the puzzle, they were the ones to form special cubists clubs, to organise competitions, to suffer from Rubik's wrist playing continuously for hours and days with an object that simply could not put down. But now, in its second incarnation, the Cube is part of a family of puzzles and games which bear the stamp of the genius who created the greatest three dimensional puzzle the world has ever known.

Erno Rubik has not changed much over the years. Working closely with Seven Towns, he is still deeply engaged in creating new games and puzzles, and remains one of the principal beneficiaries of what proved to be a spectacularly successful invention.

Design

The most important part in the manufacture of a Rubik's cube is designing the mold for the various pieces. A mold is a cavity carved into steel that has the inverse shape of the part that it will produce. When liquid plastic is put into the mold, it takes on the mold's shape when it cools. The creation of the mold is extremely precise. The cavity is highly polished to remove any flaws on the surface. Any flaw would be reproduced on each of the millions of pieces that the mold will produce. In the manufacture of the cube parts, a two piece mold is typically employed. During production, the two mold pieces are brought together to form the plastic part and then opened to release it. The tool includes ejector pins that release the molded parts from the tools as it opens. All the parts are molded with auto gating tools that automatically remove the parts from the sprue as it is ejected. The molds are also produced with a slight taper, called release angle, which aids in removal. Finally, when molds are designed, they are slightly bigger than the pieces that they ultimately will produce. This is because as the plastics cool, they shrink. Different plastics will have a different shrink rate, and each tool must be specifically designed for the material that will be used.

The commercial cube is composed of six fixed cubes, eight movable cubes on the corners and 12 movable cubes on the edges. Each cube is one of six colors. The Rubik's cube has red, yellow, blue, green, white, and orange colors. In its solved state, each color is on only one face. When the cube is rotated, the edges and corners move and the cube becomes scrambled. The challenge of the puzzle is to restore each cube to its original position. The cube is extremely challenging because there are slightly more than 43 quintillion (4.3 × 10¹⁹) possible arrangements, and only one solution.

The standard Rubik's cube has sides of about 2.2 in (5.7 cm) per square. Various other sizes have also been produced such as a 1.5 in (3.8 cm) mini cube, a 0.8 in (2 cm) key chain micro cube, and a 3.5 in (9 cm) giant cube. While the standard cube is a 3 × 3 × 3 segmentation other types have also been introduced. Some of the more interesting ones include the 2 × 2 × 2 cube, the 4 × 4 × 4 cube (called Rubik's Revenge) and the 5 × 5 × 5 cube. The shape has also been varied and puzzles in the form of a tetrahedral, a pyramid, and an octahedral are among types that were produced. The Rubik's cube also led to the development of game derivatives like the Rubik's cube puzzle and the Rub it cube eraser.

Raw Materials

The individual pieces that make up the Rubik's cube are typically produced from plastic. Plastics are high molecular weight materials that can be produced through various chemical reactions called polymerization. Most of the plastics used in a Rubik's cube are thermoplastics. These compounds are rigid, durable, and can be permanently molded into various shapes. The plastics used in the Rubik's cube are acrylonitrile butadiene styrene (ABS) and nylon. Other plastics that might be used include polypropylene (PP), high impact polystyrene (HIPS), and high density polyethylene (HDPE).

For decorative purposes, a colorant is typically added to the plastic. The pieces of a Rubik's cube are typically black. During production, colored stickers are put on the outside of the cube to denote the color of a side. The plastics that are used during production are supplied to the manufacturer in a pellet form complete with the filler and colorants. These pellets can then be loaded into the molding machines directly.

How it works

The Basics

· A Rubik's Cube is a puzzle game, the puzzle is three-dimensional, with 26 different cubes all attached to each other, each one of six different colors (red, white, blue, green, yellow, orange). They interlock to form one big, six-sided cube. Each side of the cube has nine cube sides on it. The object of the game is to turn the cubes in such a way that each side has all the cubes of one particular color.

Rotation

· The cube that is in the center of each side is actually one big cube. It is the only one that never moves--the rest of the cubes simply rotate around it. The cubes to the left and right of the center cube (12 in total) are referred to by enthusiasts as the "middle edge" pieces. They are held to an internal mechanism that allows them to rotate both up and down. Though rotating the top or bottom row of cubes gives them the appearance of moving left and right, they do not actually move in this direction.

The Corners

· The corner cubes (of which there are eight total on the entire game) are held in place to the internal mechanism similar to the way the other cubes are. They have the ability to move up and down and left and right. This allows the top and bottom rows of cubes to move in these direction. By combining a knowledge of which cubes move in which directions and which cubes don't move at all, it is entirely possible for a person to arrange the game in such a way that each side of the overall larger cube has all nine cubes of a particular color on it.

Mechanic and Mathematics of Rubik’s cube

Mechanics

Rubik's Cube partially disassembled

A standard Rubik's Cube measures 5.7 cm (approximately 2¼ inches) on each side. The puzzle consists of twenty-six unique miniature cubes, also called "cubies" or "cubelets". Each of these includes a concealed inward extension that interlocks with the other cubes, while permitting them to move to different locations. However, the center cube of each of the six faces is merely a single square façade; all six are affixed to the core mechanism. These provide structure for the other pieces to fit into and rotate around. So there are twenty-one pieces: a single core piece consisting of three intersecting axes holding the six center squares in place but letting them rotate, and twenty smaller plastic pieces which fit into it to form the assembled puzzle.

Each of the six center pieces pivots on a screw (fastener) held by the center piece, a "3-D cross". A spring between each screw head and its corresponding piece tensions the piece inward, so that collectively, the whole assembly remains compact, but can still be easily manipulated. The screw can be tightened or loosened to change the "feel" of the Cube. Newer official Rubik's brand cubes have rivets instead of screws and cannot be adjusted.

The Cube can be taken apart without much difficulty, typically by rotating the top layer by 45° and then prying one of its edge cubes away from the other two layers. Consequently it is a simple process to "solve" a Cube by taking it apart and reassembling it in a solved state.

There are six central pieces which show one coloured face, twelve edge pieces which show two colored faces, and eight corner pieces which show three coloured faces. Each piece shows a unique colour combination, but not all combinations are present (for example, if red and orange are on opposite sides of the solved Cube, there is no edge piece with both red and orange sides). The location of these cubes relative to one another can be altered by twisting an outer third of the Cube 90°, 180° or 270°, but the location of the coloured sides relative to one another in the completed state of the puzzle cannot be altered: it is fixed by the relative positions of the centre squares. However, Cubes with alternative colour arrangements also exist; for example, with the yellow face opposite the green, the blue face opposite the white, and red and orange remaining opposite each other.

Douglas Hofstadter, in the July 1982 issue of Scientific American, pointed out that Cubes could be coloured in such a way as to emphasize the corners or edges, rather than the faces as the standard colouring does; but neither of these alternative colorings have ever become popular.

Mathematics

Permutations

The original (3×3×3) Rubik's Cube has eight corners and twelve edges. There are 8! (40,320) ways to arrange the corner cubes. Seven can be oriented independently, and the orientation of the eighth depends on the preceding seven, giving 3⁷ (2,187) possibilities. There are 12!/2 (239,500,800) ways to arrange the edges, since an even permutation of the corners implies an even permutation of the edges as well. (When arrangements of centres are also permitted, as described below, the rule is that the combined arrangement of corners, edges, and centres must be an even permutation.) Eleven edges can be flipped independently, with the flip of the twelfth depending on the preceding ones, giving 2¹¹ (2,048) possibilities.

which is approximately forty-three quintillion.

The puzzle is often advertised as having only "billions" of positions, as the larger numbers are unfamiliar to many. To put this into perspective, if one had as many standards sized Rubik's Cubes as there are permutations, one could cover the Earth's surface 275 times.

The preceding figure is limited to permutations that can be reached solely by turning the sides of the cube. If one considers permutations reached through disassembly of the cube, the number becomes twelve times as large:

Which is approximately five hundred and nineteen quintillion possible arrangements of the pieces that make up the Cube, but only one in twelve of these are actually solvable. This is because there is no sequence of moves that will swap a single pair of pieces or rotate a single corner or edge cube. Thus there are twelve possible sets of reachable configurations, sometimes called "universes" or "orbits", into which the Cube can be placed by dismantling and reassembling it.

Centre faces

The original Rubik's Cube had no orientation markings on the centre faces (although some carried the words "Rubik's Cube" on the centre square of the white face), and therefore solving it does not require any attention to orienting those faces correctly. However, with marker pens, one could, for example, mark the central squares of an unscrambled Cube with four coloured marks on each edge, each corresponding to the colour of the adjacent face; a cube marked in this way is referred to as a "supercube". Some Cubes have also been produced commercially with markings on all of the squares, such as the Lo Shu magic square or playing card suits. Thus one can nominally solve a Cube yet have the markings on the centres rotated; it then becomes an additional test to solve the centres as well.

Marking the Rubik's Cube's centres increases its difficulty because this expands the set of distinguishable possible configurations. There are 4⁶/2 (2,048) ways to orient the centres, since an even permutation of the corners implies an even number of quarter turns of centres as well. In particular, when the Cube is unscrambled apart from the orientations of the central squares, there will always be an even number of centre squares requiring a quarter turn. Thus orientations of centres increases the total number of possible Cube permutations from 43,252,003,274,489,856,000 (4.3×10¹⁹) to 88,580,102,706,155,225,088,000 (8.9×10²²).

When turning a cube over is considered to be a change in permutation then we must also count arrangements of the centre faces. Nominally there are 6! ways to arrange the six centre faces of the cube, but only 24 of these are achievable without disassembly of the cube. When the orientations of centres are also counted, as above, this increases the total number of possible Cube permutations from 88,580,102,706,155,225,088,000 (8.9×10²²) to 2,125,922,464,947,725,402,112,000 (2.1×10²⁴).

Algorithms

In Rubik's cubers' parlance, a memorized sequence of moves that has a desired effect on the cube is called an algorithm. This terminology is derived from the mathematical use of algorithm, meaning a list of well-defined instructions for performing a task from a given initial state, through well-defined successive states, to a desired end-state. Each method of solving the Rubik's Cube employs its own set of algorithms, together with descriptions of what effect the algorithm has, and when it can be used to bring the cube closer to being solved.

Many algorithms are designed to transform only a small part of the cube without interfering with other parts that have already been solved, so that they can be applied repeatedly to different parts of the cube until the whole is solved. For example, there are well-known algorithms for cycling three corners without changing the rest of the puzzle, or flipping the orientation of a pair of edges while leaving the others intact.

Some algorithms do have a certain desired effect on the cube (for example, swapping two corners) but may also have the side-effect of changing other parts of the cube (such as permuting some edges). Such algorithms are often simpler than the ones without side-effects, and are employed early on in the solution when most of the puzzle has not yet been solved and the side-effects are not important. Towards the end of the solution, the more specific (and usually more complicated) algorithms are used instead.

Relevance and application of mathematical group theory

Rubik's Cube lends itself to the application of mathematical group theory, which has been helpful for deducing certain algorithms - in particular, those which have a commutator structure, namely XYX⁻¹Y⁻¹ (where X and Y are specific moves or move-sequences and X⁻¹ and Y⁻¹ are their respective inverses), or a conjugate structure, namely XYX⁻¹, often referred to by speedcubers colloquially as a "setup move".^[28] In addition, the fact that there are well-defined subgroups within the Rubik's Cube group, enables the puzzle to be learned and mastered by moving up through various self-contained "levels of Difficulty". For example, one such "level" could involve solving cubes which have been scrambled using only 180-degree turns. These subgroups are the principle underlying the computer cubing methods Thistlethwaite and Kociemba, which solve the cube by further reducing it to another subgroup.

The Manufacturing Process

The manufacture of the first Rubik's cube prototypes was by hand. During the late 1970s, methods for mass production were developed and continue to be used today. Typically, production is a step by step process that involves injection molding of the pieces, fitting the pieces together, decorating the Rubik's cube, and putting the finished product in packaging.

Molding

When production is initiated, the plastic pellets are transformed into Rubik's cube parts through injection molding. In this process, the pellets are put into the hopper of an injection molding machine. They are melted when they are passed through a hydraulically controlled screw. As the screw turns, the melted plastic is shuttled through a nozzle and physically forced, or injected, into the mold. Just prior to the arrival of the molten plastic, the two halves of the mold are brought together to create a cavity that has the identical shape of the Rubik's cube part. This could be an edge, a corner, or the center piece. Inside the mold, the plastic is held under pressure for a specific amount of time and then allowed to cool. While cooling, the plastic hardens inside the mold. After enough time passes, the mold halves are opened and the cube pieces are ejected. The mold then closes again and the process begins again. Each time the machine moulds a set of parts is one cycle of the machine. The Rubik's cube cycle time is around 20 seconds.
After the cube parts are ejected from the mold, they are dropped into container bins and hand inspected to ensure that no significantly damaged parts are used. The waste sprue material is set aside to be reused or scrapped. Waste material can be ground up and melted again to make new parts, however reground material can degrade and cause poor quality parts. Rubik's cubes are always made from virgin material and never use reground waste plastic.

Parts assembly

The Rubik's cube parts are taken to an assembly line. In this phase of production, the individual cube pieces are put together. Starting with the nylon core, each ABS center cube is riveted to the core with a spring spacer. The rivet is carefully controlled with a depth stop to ensure the spring is compressed just the right amount. Each center cube has a plastic cover that is glued on to hide the rivet. One of the six center cubes is left until the last part of the assembly. The ABS edges and corner pieces are individually stacked around the core. The cube is built from the bottom up and the last piece to be assembled is the final center cube which is again riveted into the core with a spring spacer and the final cap is glued on.

Labeling

Next, the Rubik's cube faces need to be labeled. The labels are made from sheet polypropylene material that is printed with the colors. The printed sheet PP is then laminated with a clear PP protective covering. The material is then die cut with the labels wound onto rolls. The labels are made with all nine squares of each face exactly aligned. This way the labels can be perfectly aligned when they are applied to the cube.

Packaging

After all the labeling is completed, the cubes are put in their final packaging. This can be a small box that has an instruction booklet included or a plastic blister pack with a cardboard backing. The package serves the dual purpose of protecting the Rubik's cube from damage caused by shipping and advertising the product. The Rubik's cube packages are put into cases and moved to a pallet. The pallets are then loaded on trucks and the products are shipped all over the world.

Quality Control

To ensure that each toy will be a high quality product, quality control inspectors check the product at each phase of production. The incoming plastic pellets are chemically tested to determine whether they meet certain chemical specifications. These include checks on appearance, color, melting point, toxicity, and molecular weight.

The qualities of the individual parts are also inspected just after exiting the mold. Since thousands of parts are made daily, a complete inspection would be difficult. Consequently, line inspectors may randomly check the plastic parts at fixed time intervals and check to ensure they meet size, shape, and consistency specifications. This sampling method provides a good indication of the quality of the overall Rubik's cube production run. Things that are looked for include deformed parts, improperly fitted parts and inappropriate labeling. While visual inspection is the primary test method employed, more rigorous measurements may also be performed. Measuring equipment is used to check the length, width, and thickness of each part. Typically, devices such as a vernier caliper, a micrometer, or a microscope are used. Just prior to putting a cube in the packaging it may be twisted to ensure that it holds together and is in proper working order. This can be done by hand or by a turning machine. If a toy is found to be defective it is placed aside to be reworked later.

The Future

While the extreme popularity of the Rubik's cube subsided around 1984. it has recently made a significant come back. This has been a result of impressive marketing efforts by Seven Towns. In the future, this marketing effort should continue to increase sales of the Rubik's cube. In addition to the cube, other derivative puzzles have been introduced including the Rubik's snake, Rubik's triamid, and the Rubik's magic folding puzzle. It is expected that new variants will also be introduced in the near future.

World records and Guinness

Fastest time to solve a Rubik's Cube

Feliks Zemdegs

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Feliks Zemdegs at the World Cubing Championships in Bangkok, Oct 2011

Feliks Zemdegs (born 20 December 1995 in Melbourne, Australia) is an Australian Rubik's Cube speedsolver. The surname is Latvian. He bought his first cube in April 2008 inspired by speedcubing videos and tutorials on Youtube. The first unofficial time he recorded was an average of 19.73 seconds on 14 June 2008.^[1] He currently uses the Fridrich method to solve the 3x3x3 cube, Yau method to solve the 4x4x4 cube and the CLL method to solve the 2x2x2 cube.

He won the first competition he attended, the New Zealand Championships (July 2009) with an average of 13.74 seconds in the final round. He also won 2x2, 4x4, 5x5, 3x3 Blindfolded, and 3x3 One-Handed.

At his next competition, the Melbourne Summer Open (January 2010), he set his first world records for 3x3x3 and 4x4x4 average, with times of 9.21 seconds and 42.01 seconds respectively. Since then he has broken more records as listed in the table below.

Fastest robot to solve a Rubik's Cube

For the first time in history, a robot can now solve a Rubik's Cube faster than a human. On 11 November 2011, CubeStormer II - commissioned by ARM Holdings and built by Mike Dobson and David Gilday (all UK) from four LEGO Mindstorms NXT kits and a Samsung Galaxy S2 mobile phone – completed a scrambled 3x3 cube in 5.270 seconds at the offices of Wired magazine in London, UK.

As per official speed-cubing guidelines, the Rubik's Cube was scrambled using 20 turns determined by a scrambling algorithm. The CubeStormer II robot uses the phone's camera to view the cube and an Android app "brain" determines a solution optimized for the robot's four-handed grip mechanism – i.e., not necessarily the solution with the fewest moves but the solution that the robot can achieve most effectively. What makes the total time even more impressive is that it includes image capture, calculation and physical solving time; by comparison, humans can spend time inspecting the cube and thinking about possible solutions before starting their solve. The human record, held by Feliks Zemdegs (Australia), stands at 5.66 seconds as of 18 February 2012.

Resources

1. Guinness records 2011

2. Time magazine

3. The new encyclopedias Britannica

4. Notes on Rubik’s magic cube book

5. http://www.ideafinder.com/history/inventions/rubikcube.htm

6. http://edition.cnn.com/2012/10/10/tech/rubiks-cube-inventor/index.html

7. http://www.dailymail.co.uk/news/article-1112396/Driven-mad-Rubiks-nut-weeps-solving-cube--26-years-trying.html

8. http://en.wikipedia.org/wiki/Rubik%27s_Cube

9. http://games.yahoo.com/blogs/plugged-in/5-tips-solving-rubik-cube-235839219.html

10. http://www.rubikssolver.com/